The present invention relates to a method of producing a magnetic head device for use with a magnetic disk driving device for recording or reproducing information with respect to a disk-like magnetic recording medium.
Such a magnetic disk driving device for recording or reproducing information with respect to a disk-like magnetic recording medium (which will be hereinafter referred to as a disk) is widely used as an external storage for an information processing apparatus such as computer and word processor.
An example of the information processing apparatus is a so-called still video floppy disk driving device. The disk driving device is installed in a still video floppy camera, and it is designed to record video information on a still video floppy disk in the same manner as with a camera device using a photosensitive film.
This type of disk driving device is disclosed in Japanese Utility Model Publication No. 42-17806, for example.
This reference relates to a device for recording and reproducing a signal as rotating a very thin magnetic disk sheet of 50 .mu. or less thick at a high speed such that the magnetic disk sheet can be maintained under a planar condition by a centrifugal force. A base mounting the sheet thereon is formed with a recess where a magnetic head is adjustably received. The recess is slightly inclined in a direction opposite to a rotative direction of the sheet in accordance with deformation of the sheet passing over the recess. During the rotation of the sheet, the pressure between the magnetic sheet and the base is rendered slightly smaller than the pressure over the magnetic sheet, resulting that the magnetic sheet is sunk into the recess. Accordingly, the contact between the magnetic sheet and a head gap of the magnetic head projecting upwardly from a head mounting surface may be stabilized.
In this prior art, the disk sheet is flexed as if it were sucked into the recess to face the head gap of the magnetic head under a constant condition. Accordingly, it is possible to maintain a constant video quality in recording and reproducing information without the necessity of especially restricting the position of the disk sheet with respect to the head gap.
In this kind of conventional technique, it is particularly important to maintain a stable sliding contact condition between the magnetic sheet rotating at a high speed and the magnetic head, so as to establish stable recording and reproducing with high reliability. To this end, it is necessary to project the magnetic head by a predetermined amount from a magnetic sheet sliding contact surface of the head mounting member.
Such a magnetic head device including a mechanism for adjusting a projection amount of the magnetic head is disclosed in Japanese Patent Laid-open Publication No. 61-9869, for example.
FIG. 14 shows a schematic illustration in section of the magnetic head device in this prior art. Referring to FIG. 14, the magnetic head device includes a magnetic sheet 1 adapted to be rotated by a motor, a magnetic head 2 for recording and reproducing information with respect to the magnetic sheet 1, and a head contacting member 3 for bringing the magnetic head 2 into slide contact with the magnetic sheet 1. The head contacting member 3 includes a body 5 formed with a tapering surface 4 opposed to the magnetic sheet 1. The tapering surface 4 contacts the magnetic sheet 1 at one end and inclined in such a manner that a distance between the magnetic sheet 1 and the tapering surface 4 is gradually increased from the one end to the other end along a direction of a recording track of the magnetic sheet 1. The body 4 is formed at its central portion with a magnetic head mounting space 6 for mounting a magnetic head 2 in such a manner that a head gap of the magnetic head 2 is adjustably projected from the tapering surface 4 toward the recording surface of the magnetic sheet 1. The magnetic head 2 is fixed to one end of a base 7, and the base 7 is mounted at its center to an inner wall of the space 6 by a screw 8. Lead wires 9 and 10 extending from an exciting coil of the magnetic head 2 are soldered to connection conductors 11 and 12 formed on the base 7, respectively. The projection amount of the head gap projecting from the tapering surface 4 is adjusted by slightly loosening the screw 8 and moving the base 7 in a direction depicted by arrow in FIG. 14.
In the construction of the prior art as mentioned above, the magnetic head 2 is mounted to the base 7 which is mounted by the screw 8 in the space 6 formed in the head contacting member 3. Thus, many parts are required to render the structure complicated. Further, the fine adjustment of the projection amount of the magnetic head 2 is difficult because the projection amount is finely varied upon tightening of the screw 8. As a result, the sliding contact condition of the magnetic sheet 1 with respect to the magnetic head 2 is rendered unstable, and the reliable recording and reproducing cannot be ensured. Moreover, the unstable sliding contact condition causes a problem such that the magnetic sheet 1 will be struck against the magnetic head 2 or the head contacting member 3, and a protective layer covering the recording surface of the magnetic sheet 1 will be damaged to cause deposition of ferrite (Fe) forming the recording surface to the magnetic head 2, resulting in a short life of the magnetic head 2 and the magnetic sheet 1.